Recording of electric signal passing through a pylon in direct skeletal attachment of leg prostheses with neuromuscular control.

Department of Physical Medicine and Rehabilitation, Tufts University School of Medicine, Boston, MA 02111, USA. mpitkin@tuftsmedicalcenter.org

Abstract

Direct recordings were made of electrical signals emanating from the muscles in a rabbit's residuum. The signals were transmitted via wires attached on one end to the muscles, and on the other to an external recording system. The cable was held in a titanium tube inside a pylon that had been transcutaneously implanted into the residuum's bone. The tube was surrounded by porous titanium cladding to enhance its bond with the bone and with the skin of the residuum. This study was the first known attempt to merge the technology of direct skeletal attachment of limb prostheses with the technology of neuromuscular control of prostheses, providing a safe and reliable passage of the electrical signal from the muscles inside the residuum to the outside recording system.

A – the implant SBIP-PNI with silicon shield 1 for wire electrodes 2 passing through the tube 3 surrounded by the porous cladding 4.B – a portion of the implant below the dashed arc is to be positioned in the bone of the residuum, schematically drawn as a cylinder 5 with the hole 6 for releasing the electrodes from the medullary canal for implanting to the muscle or nerve; the portion above the dashed arc is to be outside of the residuum.

Setting of the signal acquisition and recording: A - the connector 1 that leads to the implanted electrodes retrieved from the protective silicon pocket for attachment to the amplifier;B – outer part 1 of the implanted pylon SBIP-PNI tethered to the data acquisition unit 2 and the computer 3.